What was found
DURING DECENT THE CREW HAD A CASS MESSAGE WITH LOW HYDRAULICS. THEY THEN NOTICED THAT THE COMBINED HYDRAULIC SYSTEM WAS INDICATING LOW. THEY THEN RECEIVED ANOTHER CASS MESSAGE STATING TR LOCKED. WITH LOW HYDRAULIC QUANTITY THEY WERE UNABLE TO EXTEND THE LANDING GEAR SO THEY FOLLOW THE CHECK LIST AND BLEW THE LANDING GEAR DOWN. THEY DECLARED AND EMERGENCY AND LANDED AT THEIR ALTERNATE AIRPORT. ONCE ON THE GROUND THE TECHNICIAN NOTICED HYDRAULIC FLUID COMING FROM THE LEFT ENGINE CASE DRAIN. UPON FURTHER INVESTIGATION THE TECH FOUND THE LEFT ENGINE HYDRAULIC PUMP AD FAILED